Connecting device.



H. A. HART.

CONNECTING DEVICE. APPLICATION FILED APR. 27. I915.

Patented Nov. 30, 1915.

} Witness N I I Qwvintoz 7 y "MA/1 -z Q W 5 f I i F ICE.

HAROLD A. HART, or HARTFORD, CONNECTICUT.

CONNECTING DEVICE.

Specification of Letters Patent. Patnfed Nov. 30,1915.

Application filed April 27, 1915. Serial No. 24,235.

To all whom it may concern:

.- Be it known that I, HAROLD A. HART, a

citizen of the United States, residing at Hartford, county of Hartford,State of Connecticut, have'invented certain new and useful Improvementsin connectin'g Devices,

of which the following is a full, clear, and

device the plug of which can be used-in receptacles already in use.

The following is a description of my invention, reference being had tothe accom- I panying drawings, in ,which,-' i

Figure 1 shows a plan view of the base with the plug, minus the cap,inserted. Fig. 2 is a section on the line 22, Fig. 1. Fig. 3 is adiagram showingfthe relations of the threads on the plug. Fig. 4 is aperspective detail of the base showing the thread thereon. Fig. 5 is aperspective view of the threaded portion of the plug.

Referring more particularly to the drawings, 1 .is a base block havingsecuring ears 2, 2. Y

3' is a metallic shell within which is an interrupted or quartered screwthreaded metallic portion- 4. Located axially within the shell is aninner metallic terminal 5, mounted on the base block. 6 and 7 arebinding posts electrically connected to the; terminal 5 and the screwthreaded portion ,4, respectively, as shown in dots in Fig. 1.

Theconstruction so far described, if the portion 4 were not quartered,would be substantially the old construction" of base receptacles.

8 is a porcelain core for the plug. Mounted on this core is a metallicmember'9 having interrupted or quartered screw threaded surfaces 10 and11 presenting independent surfaces engaging the screw threads on thebase as hereinafter described. Each of thesesurfaces has portions of athread of the same pitch as the thread in the portion 4C. In the formshown the threading on the plug is sectioned or interrupted by therecessed portions 12,12. Thecore carries an axially located metalliccontact piece 18 which is' connected to an external circuit terminal11,. The metallic member 9 is electrically connected to a correspondingeX- ternal circuit terminal 15. The external circu it terminals 1-1 and15 are adapted to re-v .ceive two plugs from. anordinary detachablecord, and constitute no partof my invention.

16 is a cap member secured in place by a. screw passing through the sameand the core and into the contact 13, and has the usual openings for theplugs connected to the removable cord.

IVith my plug and socket each having into the receptacle by alongitudinal movement so that when the contact 13 is in engagement withthe inner terminal 5 it can be tightened up by a partial turn, whichcauses the screw threads to engage and draw the contact 13 into closerengagement with the inner terminal 5 on the :base block, thusestablishing proper electrical connections between the binding posts 6,7 and the clipterminals 1d and 15. This is a very simple and convenientarrangement for securing the plug in the base receptacle. I have found,however, that my improvement just -described is open to the objectionthat unless the plug is held in a certain angular position when insertedlongitudinally the quartered threads the plug can be inserted thread ofthe plug will not engage with the thread of, the base so as to properlysecure the plug by a quarter turn of the plug. In

' order to remove this objection I provide the plug with a plurality ofthreads of the same pitch as the thread on the base and equallysubdividing the. engaging "surface on the plug. VVith such a pluralityof threads there is always a thread on the plug which is in position to'easily engage the thread on the base receptacle, so that when theterminals '5 and 13 are brought into engagement with each other by alongitudinal movement of the plug a quarter turn of the plug willalwayssecure thev plug in proper position, as shown in Figs. 1 and 2. I havefound that two such threads, 17, 18, are suflicient.

In a double threaded plug the threads, if complete, would be as. shownin Fig. 3, the two threads being parallel and beginning at diametricallyopposite points in "the same plane, so that the two points lying in anyplane perpendicular to the axis of the plug and belong'ingto differentthreads are at diametrically opposite points relatively to said plug.Fig. 3 shows one of two threads in full lines and the other in dots.

In forming what I call interrupted or quartered screw threaded portions,I remove or recess parts of the members carrying those portions alongpaths parallel to the.

thereof of the scope of the appended claims.

What I claim is: a 41. In an electrical connecting device, the

combination of a receptacle having a quar- 'tered 11113811131SCI'GWjhI'GHd and an axially located inner terminal, and a plug having aquartered screw threaded portion and an to said plug.

end contact engaging said internal screw thread and. inner terminalrespectively, said quartered screw threaded portion having two parallelthreads of substantially the same pitch as the said internal screwthread;

2. In an electrical connecting device, the combination of a receptaclehaving a quartered internal'screw thread and aninner terminal, and aplug having a quartered screw threaded portion and an endcontact foren-- gaging said internal screw thread and inner terminal respectively,said quartered screw threaded portion having two parallel threads ofsubstantially the same pitch as the said internal screw thread, theportions of said two threads lying in the same plane being atdiametrically opposite points relatively HAROLD A. HART. lVitnessesSYLVIA' C. Mooor,

SAMUEL F. MEYER.

